Generation of reactive atomic species of positive pulsed corona discharges in wetted atmospheric flows of nitrogen and oxygen

Abstract

The emission spectra of excited radicals (OH (A2Σ), O (3p5 P), Hα (3P)) and emissive species ( N2 (C3Πu)) produced by positive pulsed high-voltage needle-plane corona discharges in atmospheric N2 and O2 flows wetted with 10% H2O at 80 °C are used to investigate the relative concentrations of the produced radicals. The results indicate that the tendencies of the concentrations of radicals with discharge conditions are similar to each other due to their similar excitation processes by electron collision. The influence of oxygen flow mixed with the nitrogen flow on the emission intensities of O (3p5P → ), Hα (3P → 2S), ( 0-0), and N2 (C3Πu → B3Πg 1-0) is presented. When the flow rate of oxygen addition is varied from 0–30 ml min−1, the emission intensities of O (3p5P → ), Hα (3P → 2s), and ( 0-0) increase and reach a maximum. Then, if the oxygen flow rate increases further, the emission intensities tend to decrease. However, the intensity of N2 (C3Πu → B3Πg 1-0) decreases monotonously with the increasing oxygen flow, which indicates that the electron density decreases with the increasing oxygen flow. By the tendencies of the relative intensities to N2 (C3Πu → B3Πg 1-0), the concentrations of the total produced O, H, and are shown to increase with the oxygen flow. Based on the reactions for the production of H and O without and with the addition of O2, the analytic solutions for H and O production are derived in accordance with the experimental results.